The possible association between genital powder use and ovarian cancer has generated controversy for several decades, with some studies showing a positive association between the practice and cancer risk and other studies negating the connection. The JAMA study, the largest to date, revealed an estimated incidence of ovarian cancer of 61 per 100,000 person-years in women who had ever used powder in the genital area, compared with 55 in 100,000 person-years in those who had never used powder genitally. The difference is not statistically significant. Moreover, there was no link between higher doses or more frequent use of powder and ovarian cancer. “Women should feel reassured by this study,” says Dana R. Gossett, MD, a professor of obstetrics, gynecology, and pediatric gynecology at the University of California in San Francisco, who wrote an editorial accompanying the study but was not involved in the research. “If there was a substantial association between genital powder use and ovarian cancer, this is a well-designed study that would have identified it.” The new study could affect dozens of lawsuits against talcum powder manufacturers by women who claim the product caused or contributed to their cancer. RELATED: Cancer Risk Genes: Everything You Need to Know About PALB2
Ovarian Cancer and Talcum Powder: An Unsettling History
There are no studies showing a direct cause-and-effect link between powder and ovarian cancer, and previous studies have produced mixed results. A 2013 paper published in Cancer Prevention Research, for instance, looked at more than 8,500 ovarian cancer cases and more than 9,800 healthy women and concluded that use of genital powder was associated with a modest increased risk of ovarian cancer. A study published in September 2014 in the Journal of the National Cancer Institute, however, found no link. “There has been controversy over how believable the results of previous studies were,” says Katie M. O’Brien, PhD, a staff scientist in the epidemiology branch at the National Institute of Environmental Health Sciences and the lead author of the JAMA paper. That’s left the significant number of women who use powder in this way in an uneasy position. About 49 percent of older U.S. women and about 26 or 27 percent of younger women say they have used powder by sprinkling it in underwear or on menstrual pads or tampons, according to the authors of the study. About 22,500 U.S. women are diagnosed with ovarian cancer each year. Because its symptoms, such as fatigue, bloating, and abdominal pain, often occur only late in the disease, it’s often diagnosed at an advanced stage, when the chances for a cure are low. Almost 14,000 American women die of the disease per year. “Ovarian cancer is a rare disease, but it’s a deadly one,” says Dr. O’Brien. “We are interested in anything that might be a cause of the disease.” RELATED: Lynch Syndrome 101: What You Need to Know
A Study Designed to Dispel Doubt
The new study aimed to address the disparities in previous research. O’Brien and her colleagues pooled data from four large U.S. cohort studies: the Nurses’ Health Study, Nurses’ Health Study II, Sister Study, and the Women’s Health Initiative Observational Study. The analysis included 257,044 women, including 2,213 who developed ovarian cancer while participating in the study. Researchers looked at self-reported genital powder use and other factors, such as patient age, whether the women had had a hysterectomy, and tubal ligation. Unlike previous studies that asked women who had already been diagnosed with ovarian cancer if they had ever used powder in the genital area, the new analysis focused on prospective studies, meaning they tracked participants’ health and lifestyle habits in real time. “A lot of the retrospective studies identify women who have ovarian cancer and ask about exposures prior to their developing ovarian cancer,” says O’Brien. The problem with the design of these studies is what’s known as recall bias, says O’Brien. “Women who have ovarian cancer might be more likely to report something that they have heard may be a cause of ovarian cancer.” The design of the current study is superior, says Dr. Gossett. “No study is perfect, but this study has pulled together data from four of the largest studies to get a really substantial number of women, with a long period of follow-up, to try to figure out the answer to this question,” Gossett said. While the researchers stopped short of saying the question over the link between use of powder and ovarian cancer is settled for good, they are reasonably confident that’s the case. “If women feel it’s important to their hygiene routine to use genital powder, they should take comfort in this study and be assured they are not doing something that substantially risks harming their health,” Gossett said. RELATED: Why I Had My Breasts and Fallopian Tubes Removed Due to a Gene I Inherited From My Dad
